1. Field of the Invention
The present inventive concept relates to a method of fabricating a light-emitting apparatus and a light-emitting apparatus fabricated using the method.
2. Description of the Related Art
Light-emitting apparatuses such as light-emitting diodes (LEDs) emit light when electrons combine with holes. Light-emitting apparatuses consume low power, have a long life, can be installed in a limited space, and are resistant to vibrations.
A major challenge in the development of light-emitting apparatuses is to improve light extraction efficiency. Light extraction efficiency is the proportion of light, which exits a light-emitting apparatus into, for example, air or transparent resin that surrounds the light-emitting apparatus), in light generated within the light-emitting apparatus. A light-emitting apparatus may have an optical refractive index of approximately 2.2 to 3.8, air may have an optical refractive index of 1, and transparent resin may have an optical refractive index of approximately 1.5.
For example, when a light-emitting apparatus has an optical refractive index of 3.4, a portion of light generated within the light-emitting apparatus may exit the light-emitting apparatus into the air at a critical angle of approximately 17 degrees and into transparent resin at a critical angle of approximately 26 degrees.
In this case, the light extraction efficiency of the light-emitting apparatus is approximately 2.2% when a portion of light generated within the light-emitting apparatus exits the light-emitting apparatus into the air, and the light extraction efficiency of the light-emitting apparatus is approximately 4% when the portion of the light generated within the light-emitting apparatus exits the light-emitting apparatus into transparent resin. The other portion of the light is reflected by a surface of the light-emitting apparatus and trapped in the light-emitting apparatus.